Clothes dryer

ABSTRACT

A clothes dryer so designed that a rotary drum will not start rotating even when a little child enters therein and closes an access door, unless a pushbutton type starting switch provided on the dryer is depressed externally.

O United States Patent 11 1 11 1 3,713,226 Takeyama et al. 1 1 Jan. 30,1973 [54] CLOTHES DRYER [56] References Cited [75] Inventors: KojiroTakeyama, Kawanishi; UNITED STATES PATENTS Hajime Onishi, Osaka, both ofJapan 3,404,466 10/1968 Reid ..34 53 3,57l,945 3/l-97l Elders ..34/53[73] Assignee: Matsushita Electric Industrial Co. 3,624,918 12/1971Heftler 1 ..34/48 Ltd., Osaka, Japan 3,662,475 5/1972 Beller et al...34/45 [22] Fied: 1971 Primary ExaminerCarroll B. Dority, Jr. [21]Appl. No.: 188,136 Attorney-Stevens, Davis, Miller & Mosher 57 ABSTRACT[30] Foreign Application Priority Data- I A clothes dryer so designedthat a rotary drum will not Oct. 20, Japan Start rotating e hen a ente st erein and closes an access door, unless a pushbutton type "32/2562;Starting switch provided on the dryer is depressed l'l terna" [58] Fieldof Search ..34/45, 48, 53 y 3 Claims, 3 Drawing Figures \a 3 5 9'4 I o oTo 43 ll 36 E A PATENTEU JAN 30 I975 sum 1 0F 2 1 CLOTHES DRYERBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a safety device of a clothes dryer of the type having arotary drum.

2. Description of the Prior Art Conventional clothes dryers of the typedescribed have been provided with a safety device such as a door switchand designed such that the rotary drum do not rotate unless and until anaccess door of the dryer is closed.

However, the'door switch only is insufficient to ensure the safety ofthe dryers. For instance, when little children enter the rotary drum andclose the access door internally, the rotary drum starts rotating,possibly resulting in loss of the lives of the children. Therefore,safer clothes dryers have been desired recently which are designed suchthat the rotary drum will not start rotating even when a time switch isswitched on and the access door is closed, unless and until a startingswitch is depressed.

SUMMARY OF THE INVENTION The present invention has been achieved to meetsuch desire and a first object of the invention is to provide a clothesdryer in which a capacitor motor is employed for driving the rotary drumso as to provide for the use of a relay of a simple construction for theselfholding of the starting switch.

A second object of the invention is to a clothes dryer of the characterdescribed above, in which the movable contact plate of the startingswitch is carried on an attraction member magnetically operated by therelay coil, so that said movable contact plate and said attractionmember may be directly depressed by a pushbutton, whereby a reliablecircuit closing operation of the starting switch can be obtained andfurther the starting switch can be rendered very simple in constructionand inexpensive as compared with the type in which the movable contactplate is indirectly depressed by the pushbutton.

A third object of the invention is to provide a clothes dryer of thecharacter described above, in which the starting switch is assembledinto a compact unitary piece so that it may be mounted on or demountedfrom the clothes dryer simply by inserting or removing it into or from amounting hole formed in the cabinet of the clothes dryer.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially broken away andpartially sectional vertical cross sectional view of an embodiment ofthe clothes dryer according to the present invention;

FIG. 2 is a partially sectional enlarged view showing the essentialportion of the clothes dryer; and

FIG. 3 is an electrical connection diagram of the clothes dryer.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of thepresent invention will be described hereunder with reference to theaccompanying drawing. Referring to FIG. 1, a rotary drum 2 is rotatablymounted within an appearance cabinet 1 for rotation about a horizontalaxis. A capacitor motor 3 to drive the rotary drum 2 and an exhaust fan4 is mounted on the bottom wall of the cabinet 1 by means of a bracket23'. The front wall of the rotary drum 2 is formed with an accessopening 5 for loading and unloading clothes and the access opening 5 isclosed by a door 6 hingedly mounted on the cabinet 1. A door switch 7 isprovided on the cabinet 1 adjacent the door 6 to be opened and closed inresponse to the opening and closing operation of said door. The frontwall of the rotary drum 2 is formed therein with a number of apertures8. A heater mounting plate 9 with an electric heater 10 mounted thereonis provided generally co-extensive with the apertures 8 formed in thefront wall of the rotary drum 2. The electric heater 10 is electricallyinsulated from the mounting plate 9 by an insulator 11 mounted on saidplate. The heater mounting plate 9 is formed with an inward flange 12along the inner peripheral edge thereof which rotatably supports thefront wall of the rotary drum 2 through a Teflon sheet 13 having a smallcoefficient of friction. The back wall of the rotary drum 2 is formedwith a central opening and a screen filter 14 made of nylon of the likeis stretched over said opening. The filter 14 is covered by a filtercover 15 from the inside of the rotary drum 2, which is made ofpolypropylene or the like and held in position by an annular projection2' formed along the inner peripheral edge of the opening in the backwall of the rotary drum and engaging the outer peripheral portion ofsaid filter cover. This filter cover 15 holds the filter 14 by embracingthe peripheral edge thereof while being resiliently supported by theannular projection 2' and can be mounted and demounted easily. A flatbelt 16 is engaged around a pulley 17 mounted on the driving shaft ofthe motor 3 and the outer peripheral surface of the rotary drum 2 totransmit the driving force of said motor to said rotary drum to rotatethe latter. The belt 16 is held taut by an idle pulley 18. Further, abelt 19 is engaged around a pulley 20 mounted on the driving shaft ofthe motor 3 and'a pulley 22 mounted on the shaft 21 of the exhaust fan 4to transmit the driving force of said motor to said exhaust fan to drivethe latter. The exhaust fan 4 is enclosed by a fan case 23. The fan case23 is formed with a flange 24 on the suction side which extends inwardlyof the dryer to rotatably support the back wall of the rotary drum 2through a Teflon sheet 25 having a small coefficient of friction. On theinner surface of the rotary drum 2 are provided a plurality ofsubstantially semicylindrical baffle plates 26 each made of a plasticmaterial such as polypropylene and formed with a number of apertures 27in the rear portion thereof. These baffle plates 26 serve to assist intumbling and free fall of the articles to be dried within the rotarydrum 2. The cabinet 1 is formed at the lower portion of the back wallthereof with an inlet opening 28 in register with the motor 3. Thecabinet 1 is provided with universal wheels 29 at the bottom thereof.The rotary drum 2 also has opening 30 formed in the front wall thereofin register with the respective baffle plates 26. A thermostat 3l'isprovided on the fan case 23 to detect the exhaust temperature. Anotherthermostat 32 is provided on the heater mounting plate 9 for theprevention of overheating of the rotary drum 2. The fan case 23 isformed with an exhaust opening 33. A time switch 34 is mounted on theupper portion of the front wall of the cabinet 1, which opens and closesthe contacts in the motor circuit and the heater circuit according to apreset timing as shown in FIG. 3.

A starting switch 35 is mounted on the cabinet 1 above the time switch34 and the construction thereof will be described hereunder withreference to FIG. 2. The starting switch 35 comprises a relay coil 36having two terminals 36', a substantially U-shaped retainer frame 37 onthe rear wall portion 37' of which said relay coil 36 is mounted througha bracket 38 by means of a screw 39 or the like, a fixed contact plate40 secured to the upper wall portion of said bracket 38 through aninsulation plate 41 by means of a screw 40 or the like and having afixed contact 42 thereon, a movable contact plate 43 arranged in opposedrelation to said fixed contact plate 40 and carried on an attractionmember 45 through an insulation plate 44, a tension spring 46 having oneend anchored to said bracket 38 and the other end to the lower end ofsaid attraction member 45 to bias said attraction member into a-positionspaced from said relay coil 36, said movable contact plate 43 and saidattraction member 45 and said insulation plate 44 being tightenedtogether by means of screws 47, a pushbutton 48 arranged in opposedrelation to said movable contact plate 43 and made of an insulatingmaterial, said pushbutton 48 having a cylindrical portion 48' which issupported by a frame member 51 extending from the bottom wall portion 49to the upper portion 50 of the front wall portion 52 of said U-shapedretainer frame 37 and a button portion 48" which is projecting forwardlyoutwardly from said front wall portion 52 of said U-shaped retainerframe 37 and the front wall of the cabinet 1, and a spring 55 mountedaround the cylindrical portion 48 of said pushbutton 48 to hold saidpushbutton 48 in a position spaced from the movable contact plate 43.

Now, the electric circuit of the clothes dryer will be described withreference to FIG. 3. The starting switch 35 is provided between a powersource 56 and the time switch 34 and connected in series with the doorswitch 7 and said time switch 34. The door switch 7 is also connected inseries with the time switch 34. Further, the relay coil 36 of thestarting switch 35 is connected between points A and B at which anelectrical load is imposed. Reference numeral 57 designates a capacitorfor driving the motor 3 and 58 designates a timer motor for driving thetime switch 34.

The clothes dryer constructed as described above will operate in thefollowing manner: Namely, first of all, articles to be dried are loadedin the rotary drum 2 and the time switch 34 is rotated into an ONposition. Then, the door 6 is closed, whereupon the door switch 7 isplaced in an ON position. However, the clothes dryer does not yetoperate in this state. Then, the pushbutton 48 of the starting switch isdepressed in the direction of the arrow C shown in FIG. 2 against thebiasing force of the spring 55. Thus, the movable contact plate 43 isbrought into contact with the fixed contact plate 40 and at the sametime, the attraction member 45 is attached to the relay coil 36, wherebysaid relay coil 36 is energized. By the energization of the relay coil36, the rotary drum 2 rotates at the rate of about 50 revolutions perminute and the exhaust fan 4 at the rate of about 2,000 revolutions permi'nute. The

electric heater l0 isalso energized upon contact of the movable contactplate 43 with the fixed contact plate 40. Since the movable contactplate 43 is held in its closed position by the energized relay coil 36,the clothes dryer continues its operation even after the pressure isreleased from the pushbutton 48.

Therefore, the external air enters the cabinet 1 from the air inletopening 28 formed at the lower portion of the back wall of the cabinet 1rearwardly of the motor 3, passes around the motor 3 while cooling saidmotor and flows toward the heater mounting plate 9 as indicated by thearrows shown in FIG. 1. The air flows further into the spacing betweenthe heater mounting plate 9 and the rotary drum 2 and thence into therotary drum 2 through the apertures 8 formed in the front wall of therotary drum 2 and the opening 30 communicating with the interior of therespective baffle plates 26, after being heated by the electric heater10. Since each baffle plate 26 is formed with the apertures 27 at onlythe rear portion thereof, the heated air entering the rotary drum 2 fromsaid apertures 27 and the apertures 8 in the front wall of said rotarydrum flows everywhere within said rotary drum. The hot air emerging fromthe rotary drum 2 is cleared of fibrous dusts during passage through thefilter cover 15 and the filter l4, and the humid hot air only isexhausted to the outside of the cabinet 1 through the exhaust opening33.

When the door 6 is opened or the time switch 34 is turned off during thedrying operation, the dryer stops its operation. For re-starting thedryer, the time switch 34 is rotated once again into its ON position andthe door 6 is closed, and then the starting switch 35 is depressed. Evenif the two thermostats 31, 32 are actuated and the contacts thereof areopened during the drying operation, the drying operation will not beinterrupted because the circuit including these thermostats and thecircuit of the relay coil 36 are connected in parallel with each other.

We claim:

1. A clothes dryer comprising an appearance cabinet, a rotary drumrotatably mounted within said cabinet for rotation about a horizontalaxis, a capacitor motor' for driving said rotary drum, an access openingformed in the front wall of said rotary drum for loading and unloadingclothes, a door openably mountedon said cabinet for closing said accessopening, a door switch operated in response to the opening and closingoperations of said door, a time switch connected in series with saiddoor switch and a starting switch connected in series with said timeswitch and said .door switch, said starting switch consisting of aself-holding switch including a relay, a movable contact plate, and apushbutton arranged in opposed relation to the movable contact plate ofsaid starting switch.

2. A clothes dryer as defined in claim 1, wherein said starting switchis provided between a power source and said time switch and its movablecontact plate is directly carried on a member adapted to be magneticallyattracted by the relay coil so that said movable contact plate and saidmember may be depressed directly by said pushbutton.

3. A clothes dryer as defined in claim 2, wherein said starting switchincludes a substantially U-shaped retainer frame secured to the cabinet,and said relay coil, said member, the movable and fixed contact platesof said starting switch and said pushbutton are integrally mounted onsaid retainer frame in the form of a unitary piece of assembly, saidU-shaped retainer frame being secured to the cabinet at the front wallportion thereof with said pushbutton projecting outwardly of 5 saidcabinet.

1. A clothes dryer comprising an appearance cabinet, a rotary drumrotatably mounted within said cabinet for rotation about a horizontalaxis, a capacitor motor for driving said rotary drum, an access openingformed in the front wall of said rotary drum for loading and unloadingclothes, a door openably mounted on said cabinet for closing said accessopening, a door switch operated in response to the opening and closingoperations of said door, a time switch connected in series with saiddoor switch and a starting switch connected in series with said timeswitch and said door switch, said starting switch consisting of aself-holding switch including a relay, a movable contact plate, and apushbutton arranged in opposed relation to the movable contact plate ofsaid starting switch.
 1. A clothes dryer comprising an appearancecabinet, a rotary drum rotatably mounted within said cabinet forrotation about a horizontal axis, a capacitor motor for driving saidrotary drum, an access opening formed in the front wall of said rotarydrum for loading and unloading clothes, a door openably mounted on saidcabinet for closing said access opening, a door switch operated inresponse to the opening and closing operations of said door, a timeswitch connected in series with said door switch and a starting switchconnected in series with said time switch and said door switch, saidstarting switch consisting of a self-holding switch including a relay, amovable contact plate, and a pushbutton arranged in opposed relation tothe movable contact plate of said starting switch.
 2. A clothes dryer asdefined in claim 1, wherein said starting switch is provided between apower source and said time switch and its movable contact plate isdirectly carried on a member adapted to be magnetically attracted by therelay coil so that said movable contact plate and said member may bedepressed directly by said pushbutton.